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Livestock Weight Calculator

Weigh Cattle, Sheep and Pigs With a Tape

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How the Livestock Weight Calculator works

This livestock weight calculator estimates the live weight of cattle, sheep, goats and pigs from two tape measurements, heart girth and body length. It is a quick way to dose wormers, plan feed or track growth when you do not have a weighbridge or scales.

How the livestock weight calculator works

Measure heart girth round the chest just behind the front legs, and body length from the point of the shoulder to the pin bone at the base of the tail. The animal should stand square with its head up. The formula is weight in pounds = girth² × length ÷ 300 for cattle, sheep and goats, with lengths in inches. Pigs carry more weight for their size, so their divisor is 400. Centimetre measurements are converted to inches first, and the result is shown in both pounds and kilograms.

First example. A steer with a heart girth of 72 in and a body length of 60 in weighs about 72² × 60 ÷ 300 = 1,037 lb (470 kg), with a likely range of 985 to 1,089 lb.

Second example. A pig with a 40 in girth and 38 in length weighs about 40² × 38 ÷ 400 = 152 lb (69 kg). A sheep at 30 in by 28 in comes out at about 84 lb (38 kg).

How many measurements should I take? Take each one two or three times and use the average. Tape estimates are usually within about 5 to 10% of scale weight when done carefully.

Very fat, very thin, heavily pregnant or full-fleeced animals throw the estimate off, so use a weighbridge when the exact figure matters, such as at sale.

Estimated cattle live weight by heart girth and body length (girth² × length ÷ 300)

Heart girth Length 50 in Length 55 in Length 60 in Length 65 in Length 70 in
50 in 417 lb 458 lb 500 lb 542 lb 583 lb
52 in 451 lb 496 lb 541 lb 586 lb 631 lb
54 in 486 lb 535 lb 583 lb 632 lb 680 lb
56 in 523 lb 575 lb 627 lb 679 lb 732 lb
58 in 561 lb 617 lb 673 lb 729 lb 785 lb
60 in 600 lb 660 lb 720 lb 780 lb 840 lb
62 in 641 lb 705 lb 769 lb 833 lb 897 lb
64 in 683 lb 751 lb 819 lb 887 lb 956 lb
66 in 726 lb 799 lb 871 lb 944 lb 1,016 lb
68 in 771 lb 848 lb 925 lb 1,002 lb 1,079 lb
70 in 817 lb 898 lb 980 lb 1,062 lb 1,143 lb
72 in 864 lb 950 lb 1,037 lb 1,123 lb 1,210 lb
74 in 913 lb 1,004 lb 1,095 lb 1,186 lb 1,278 lb
76 in 963 lb 1,059 lb 1,155 lb 1,251 lb 1,348 lb
78 in 1,014 lb 1,115 lb 1,217 lb 1,318 lb 1,420 lb
80 in 1,067 lb 1,173 lb 1,280 lb 1,387 lb 1,493 lb
82 in 1,121 lb 1,233 lb 1,345 lb 1,457 lb 1,569 lb
84 in 1,176 lb 1,294 lb 1,411 lb 1,529 lb 1,646 lb
86 in 1,233 lb 1,356 lb 1,479 lb 1,602 lb 1,726 lb
88 in 1,291 lb 1,420 lb 1,549 lb 1,678 lb 1,807 lb

FAQ

How do I measure heart girth?

Pass the tape round the animal just behind the front legs and shoulder blades, at the narrowest point of the chest. Pull it snug but not tight, and read it after the animal breathes out.

Where do I measure body length?

From the point of the shoulder to the pin bone, the bony point either side of the tail head. Keep the tape straight along the side of the body rather than following the curve of the back.

How accurate is a weigh tape?

Usually within 5 to 10% of scale weight for animals in average condition. Errors grow for very young, very fat, pregnant or woolly animals, so use scales for sale weights or exact drug dosing.

Why is the pig formula different?

Pigs are denser and more barrel-shaped than cattle or sheep, so the same girth and length carry more weight. The traditional pig divisor of 400 instead of 300 reflects that difference in body shape.

Can I use the result to dose wormer?

Many farmers do, but round up to the next dose band so animals are never under-dosed. Under-dosing encourages wormer resistance, and the label dose should always be based on the heaviest animal.

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